dsp01讲义

• Characterization of signals 信号描述
– signal can be described as a function of independent variables such as time, distance, position, temperature, and pressure etc.
• Processing – to perform operations on data according to programmed instructions • Which leads us to a simple definition of: – changing or analysing information which is measured as discrete sequences of numbers
– See the catalogue
DSP CAI
INTRODUCTION
4
Introduction
• What’s DSP?
– – – – Signal & signal characterization (review) Signal classification (review) System & system classification (review) Signal processing & Digital Signal Processing
Digital Signal Processing(DSP) 数字信号处理
Xia Chunlei of USST No. 516 Jungong Rd. Shanghai 200093
DSP CAI
INTRODUCTION
1
General Information
• Textbook: Paulo S. R. Diniz, Eduardo A. B. da
DSP CAI INTRODUCTION 6
• Note two unique features of Digital Signal processing as opposed to plain old ordinary digital processing: – signals come from the real world - this intimate connection with the real world leads to many unique needs such as the need to react in real time and a need to measure signals and convert them to digital numbers – signals are discrete - which means the information in discrete samples is lost
DSP CAI INTRODUCTION 11
• For a continuous-time 1-D signal, the continuous independent variable is usually denoted by t (time， 时间). E.g. u(t) is often used to represent a continuous-time 1-D signal. • For a discrete-time 1-D signal, the discrete independent variable is usually denoted by n (number， 数字). E.g. v[n] is often used to represent a discretetime 1-D signal. Each number of the discrete-time sequence, in this example, it is v[n] , is called a sample(采样). • Relationship between different signal types
DSP CAI INTRODUCTION 10
Depending on the nature of the variables
• Continuous-Time Signals（连续时间信号）
The independent variable is continuous – Analog Signals（模拟信号）：continuous-time and continuous amplitude. e.g. speech signal – Quantized boxcar signal（量化信号）： continuoustime and discrete-valued amplitudes
DSP CAI
INTRODUCTION
2
References
• A. V. Oppenheim & R. W. Schafer,数字信号处理， 科学出版社，1982 • Sophocles J. Orfanidis, Introduction to Signal Processing, Tsinghua, Beijing,1999 • Richard G. Lyons, Understanding Digital Signal Processing, 科学出版社，2003 • M. H. 海因斯，数字信号处理，科学出版社， 2002 • 程佩青，数字信号处理教程（第二版），清华 大学出版社，2002
t
t c. A sampled-data signal
DSP CAI INTRODUCTION
t d. A quantized boxcar signal
13
Depending on the certainty by which the signal can be uniquely described • Deterministic signal (确定性信号)
• Multidimensional (M-D) signal 多维信号
– A M-D Signal is a function of more than one independent variables, e.g. a back-and-white video signal or a color video signal (a RGB television signal) is a 3-D signal.
• Discrete-Time Signals（离散时间信号）
The independent variable is discrete – Digital Signals（数字信号）： discrete-time and discrete-valued amplitudes and could be represented by a finite number of digits. e.g. the digitized music signal stored in a CD-ROM disk – Sampled-data signal（采样信号）： discrete-time and continuous-valued amplitudes
DSP CAI INTRODUCTION 9
• • • •
Depending on the number of variables
• One-dimensional (1-D) signal 一维信号
– A 1-D Signal is a function of a single independent. variable, e.g. speech signal. – For a 1-D signal, the independent variable usually labeled as time.
DSP CAI INTRODUCTION 3
About the Course
• What can we learn from this course? • What shall we do for this course?
– Lessons – Exercises – Experiments
• Outline of this course
• Two-dimensional (2-D) signal 二维信号
– A 2-D Signal is a function of two independent variables, e.g. image signal or each frame of a back-and-white video signal.
DSP CAI
INTRODUCTION
7
Signal & Signal Characterization
• Signal信号
– A function of independent variables(独立变量), which conveys information about state or behavior of a physical system.
• How can we realize DSP? • Why should we choose DSP?
– Advantages of DSP
• Applications of DSP
DSP CAI INTRODUCTION 5
What is DSP?
We can start by dictionary definitoustime Signal (CTS)
DSP CAI
Sampling
Discrete-time Signal (DTS)
Quantizing
Digital Signal (DS)
INTRODUCTION
12
Figure 1. Four types of signals Amplitude Amplitude t a. an analog signal Amplitude Amplitude b. a digital signal